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CVE-2021-22901

Published: 26 May 2021

curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.

Priority

Medium

CVSS 3 base score: 8.1

Status

Package Release Status
curl
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(7.58.0-2ubuntu3.13)
focal Not vulnerable
(7.68.0-1ubuntu2.5)
groovy Not vulnerable
(7.68.0-1ubuntu4.3)
hirsute Not vulnerable
(7.74.0-1ubuntu2)
impish Not vulnerable
(7.74.0-1.2ubuntu1)
jammy Not vulnerable
(7.74.0-1.2ubuntu1)
precise Not vulnerable

trusty Not vulnerable

upstream
Released (7.77.0)
xenial Not vulnerable